Biomedical subjects

K Bell

Publications and source records attributed to K Bell.

At least 19 recordsLinked to original sources

PubMed2006

Odour emissions from anaerobic piggery ponds. 2: improving estimates of emission rate through recognition of spatial variability.

Odour emission rates were measured for seven different anaerobic ponds treating piggery wastes at six to nine discrete locations across the surface of each pond on each sampling occasion over a thirteen month period. Significant variability in emission rates were observed for each pond. Measurement of a number of water quality variables in pond liquor samples collected at the same time and from the same locations as the odour samples indicated that the composition of the pond liquor was also variable. The results indicated that spatial variability was a real phenomenon and could have a significant impact on odour assessment practices. Considerably more odour samples would be required to characterise pond emissions than currently recommended by most practitioners, or regulatory agencies.

Animals↗

PubMed2006

Hip fracture implants increase serum metal levels.

OBJECTIVE: Hip fractures are disabling accidents in the elderly. The purpose of this prospective study was to investigate systemic exposure to metals from hip implants used for fracture fixation. MATERIAL AND METHODS: Serum levels of Cr, Ni and Mo in patients with compression hip screws (n = 22) or cervical fracture screws (n = 23) were measured by inductively coupled plasma mass spectrometry. Blood samples were collected before surgery and at 3 and 12 months postoperatively. RESULTS: At 3 months, patients with compression hip screws showed higher concentrations of Cr and Ni than did those with cervical screws. Both types of screws led to a 2-fold increase in serum Mo, which was not expected for the freestanding cervical screws. After 12 months, the levels had decreased, but the compression hip screw was still associated with higher values for Cr and Mo. CONCLUSIONS: The difference between the screws is most likely due to the potential for fretting and crevice corrosion between components in the compression hip screws. The apparent short-term systemic elevation of stainless steel elements in patients with hip screws does not support routine removal of asymptomatic hip fracture implants.

Aged↗

PubMed2006

Managing peripherally inserted central catheter-related venous thrombosis: How I do it.

Imaging-guided insertion of central venous catheters, either in the form of a peripherally inserted central catheter (PICC) or through a subclavian or a jugular approach, is becoming the preferred method of acquiring long-term venous access for a variety of therapeutic purposes. The most significant complication from central venous catheters is thrombosis of the catheterized vein. Venous thrombosis related to the insertion of PICC lines is conventionally treated with line removal followed by anticoagulation. Direct thrombolysis with urokinase, using the lumen of the PICC line to facilitate the insertion of the infusion catheter is a simple, safe and effective treatment option. In this article, we describe our experience with this procedure and the technique used.

Adult↗

PubMed2005

Effect of awake Carotid Endarterectomy under local anaesthesia on peri-operative blood pressure: blood pressure is normalised when carotid stenosis is treated under local anaesthesia.

BACKGROUND: Carotid Endarterectomy can be performed under local, regional or general anaesthesia. One of the most important effects of the type of anaesthetic used is on the systemic blood pressure. Although variations in blood pressure during and following carotid endarterectomy have been studied previously, the effects of awake carotid endarterectomy under local anaesthesia on blood pressure and its comparison with similar procedures under similar types of anaesthesia have not. METHODS: Peri-operative blood pressure measurements were collected from the records of 25 consecutive patients for each of the following five procedures; Carotid Endarterectomy under general anaesthesia (CEAGA), Anterior Cervical Discectomy and Fusion under general anaesthesia (ACDF), Cerebral Angiography under local anaesthesia (ANG), Carotid Endarterectomy patients under local anaesthesia who were symptomatic (CEALAS) and Carotid Endarterectomy patients under local anaesthesia who were asymptomatic (CEALAA). The recordings were then analysed to find out if there were any clinically significant variations in peri-operative blood pressure. FINDINGS: There is a significant and consistent difference when the pre-operative value was compared with the 4 hour and 24 hour post-operative recordings between the local and general anaesthetic groups for carotid endarterectomy. Carotid endarterectomy reduces the systolic and diastolic blood pressures post-operatively when performed under local anaesthesia and only the diastolic pressure was reduced when performed under general anaesthesia. CONCLUSION: The study provides evidence about the effect of carotid endarterectomy on the systemic blood pressure and its variations when performed under different types of anaesthesia. There is significant post-operative reduction in both the systolic and diastolic blood pressure values and the intraoperative fluctuation is minimal when local anaesthesia is used. Further studies are required to find out how this affects the long-term blood pressure and clinical outcome of the patient.

Anesthesia, General↗

PubMed2005

Motor signs predict poor outcomes in Alzheimer disease.

OBJECTIVE: To examine whether the presence of motor signs has predictive value for important outcomes in Alzheimer disease (AD). METHODS: A total of 533 patients with AD at early stages (mean Folstein Mini-Mental State Examination [MMSE] 21/30 at entry) were recruited and followed semiannually for up to 13.1 years (mean 3) in five University-based AD centers in the United States and European Union. Four outcomes, assessed every 6 months, were used in Cox models: cognitive endpoint (Columbia Mini-Mental State Examination < or = 20/57 [ approximately MMSE < or = 10/30]), functional endpoint (Blessed Dementia Rating Scale > or = 10), institutionalization equivalent index, and death. Using a standardized portion of the Unified PD Rating Scale (administered every 6 months for a total of 3,149 visit-assessments, average 5.9 per patient), the presence of motor signs, as well as of individual motor sign domains, was examined as time-dependent predictor. The models controlled for cohort, recruitment center, sex, age, education, a comorbidity index, and baseline cognitive and functional performance. RESULTS: A total of 39% of the patients reached the cognitive, 41% the functional, 54% the institutionalization, and 47% the mortality endpoint. Motor signs were noted for 14% of patients at baseline and for 45% at any evaluation. Their presence was associated with increased risk for cognitive decline (RR, 1.72; 95% CI, 1.24 to 2.38), functional decline (1.80 [1.33 to 2.45]), institutionalization (1.68 [1.26 to 2.25]), and death (1.38 [1.05 to 1.82]). Tremor was associated with increased risk for reaching the cognitive and bradykinesia for reaching the functional endpoints. Postural-gait abnormalities carried increased risk for institutionalization and mortality. Faster rates of motor sign accumulation were associated with increased risk for all outcomes. CONCLUSIONS: Motor signs predict cognitive and functional decline, institutionalization, and mortality in Alzheimer disease. Different motor sign domains predict different outcomes.

Aged↗

PubMed2005

Nickel contamination from an intravenous catheter used for infusion.

At the outset of a clinical research project involving metal analyses on patients receiving metal devices in conjunction with hip fractures, unexpected high concentrations of nickel were discovered in serum samples taken before surgery. The median nickel concentration in 30 patients was 4.6 microg/l (highest 19.5 microg/l), while reference values in non-exposed persons are reported to be 0.05-1.2 microg/l. The sampling and analyzing procedures were scrutinized without positive identification of the source of contamination. A review of all relevant procedures was then undertaken. It was identified that the nickel contamination originated from the intravenous catheter which was always put in place immediately after the patient's admission to the hospital, and thus before the blood sampling. Close inspection of the intravenous catheter revealed that it contained a nickel-plated brass funnel inside the hub of the device which released nickel into the Ringer-acetate passing through the catheter. The present catheter has been the standard device used at Haukeland University Hospital for the past 6 years. Patients have consequently been exposed to small amounts of nickel. The clinical relevance of the exposure cannot be determined. For the patients included in the research project, a metal-free alternative was used. These findings show that the quality and properties of everyday medical devices should be scrutinized, at least before being used for special purposes.

Aged↗

PubMed2004

Motor signs during the course of Alzheimer disease.

BACKGROUND: Motor signs (MOSIs) are common in Alzheimer disease (AD) and may be associated with rates of cognitive decline, mortality, and cost of care. OBJECTIVE: To describe the progression and identify predictors of individual MOSIs in AD. METHODS: A cohort of 474 patients with AD at early stages was followed semiannually for up to 13.1 years (mean 3.6 years) in five centers in Europe and the United States. MOSIs were rated using a standardized portion of the Unified Parkinson's Disease Rating Scale. Overall, 3,030 visits/assessments of MOSIs (average 6.4/patient) were performed. Prevalence and incidence rates were calculated, and cumulative risk graphs were plotted for individual non-drug-induced MOSI domains. Rates of change over time taking into account potential covariates were also estimated. With use of each MOSI domain as outcome in Cox models, predictors of MOSI incidence were identified. RESULTS: At least one MOSI was detected in 13% of patients at first examination and in 36% for the last evaluation. Total MOSI score increased at an annual rate of 3% of total possible score. Rates of annual change for speech/facial expression (4%), rigidity (2.45%), posture/gait (3.9%), and bradykinesia (3.75%) were of similar magnitude, and their occurrence increased from first (3 to 6%) to last (22 to 29%) evaluation. Tremor was less frequent throughout the course of the disease (4% at first and 7% at last evaluation) and worsened less (0.75% increase/year). CONCLUSIONS: Most motor signs occur frequently and progress rapidly in Alzheimer disease. Tremor is an exception in that it occurs less frequently and advances at slower rates.

Aged↗

PubMed2004

Localised genital Norwegian scabies in an AIDS patient.

OBJECTIVES: We present a case of an AIDS patient with Norwegian scabies manifest by a single, crusted plaque localised to the glans penis. METHODS: A 45 year old man with AIDS presented to our clinic complaining of a red papular pruritic rash on his abdomen and anterior thighs and a single, thick, crusted, non-pruritic lesion on the penis. He had been treated with lindane topically prior to the development of the penile lesion without resolution of the pruritus or red papular lesions. A mineral oil preparation was obtained from the hyperkeratotic penile lesion and revealed numerous mite eggs and faeces. RESULTS: The diagnosis of localised, genital Norwegian scabies was made. The patient was treated with ivermectin 200 micro g/kg per dose taken as two doses, 14 days apart, with complete resolution of both pruritus and skin lesions. CONCLUSIONS: This patient is the first known report of Norwegian scabies localised as a single lesion on the penis. He was successfully treated with oral ivermectin monotherapy.

AIDS-Related Opportunistic Infections↗

PubMed2003

The second generation of the International Equine Gene Mapping Workshop half-sibling linkage map.

A low-density, male-based linkage map was constructed as one of the objectives of the International Equine Gene Mapping Workshop. Here we report the second generation map based on testing 503 half-sibling offspring from 13 sire families for 344 informative markers using the CRIMAP program. The multipoint linkage analysis localized 310 markers (90%) with 257 markers being linearly ordered. The map included 34 linkage groups representing all 31 autosomes and spanning 2262 cM with an average interval between loci of 10.1 cM. This map is a milestone in that it is the first map with linkage groups assigned to each of the 31 automosomes and a single linkage group to all but three chromosomes.

Animals↗

PubMed2003

The serum concentration of estradiol after embryo transfer and the decline from preovulatory levels may influence the success of IVF treatment.

AIM: To establish the influence that serum estradiol concentrations prior to oocyte retrieval and 3 days after embryo transfer have on the establishment of in vitro fertilization (IVF) pregnancy. METHOD: Preovulatory (day-0) and luteal-phase (day-6) estradiol concentrations were retrospectively analyzed in 310 infertile patients, undertaking 1st-cycle conventional IVF or intracytoplasmic sperm injection. RESULTS: The IVF treatment success is significantly reduced in patients with an estradiol level <600 pg/ml and also when a rapid decline in luteal-phase estradiol concentrations from preovulatory concentrations (day 0:day 6 ratio) was exhibited. CONCLUSION: A day 0:day 6 estradiol ratio >5 and a serum estradiol concentration <600 pg/ml may adversely impact on the establishment of pregnancy in IVF.

Adult↗

PubMed2003

Procalcitonin: a marker of bacteraemia in SIRS.

A number of European studies have documented the ability of procalcitonin (PCT), a novel inflammatory marker, to discriminate patients with sepsis from those with other causes of systemic inflammatory response syndrome (SIRS). The aim of this study was to assess procalcitonin's performance in an Australian intensive care unit (ICU) setting to examine whether it could discriminate between these two conditions. One hundred and twenty-three consecutive adult ICU patients fulfilling criteria for SIRS were enlisted in the study. Over a period of five days, daily serum PCT and C-reactive protein (CRP) levels were measured. At least two sets of cultures were taken of blood, sputum/broncho-alveolar lavage (BAL) and urine. Other cultures were taken as clinically indicated. Questionnaires to ascertain clinical suspicion of sepsis were prospectively answered by the ICU senior registrars. PCT values were ten times higher in patients with positive blood cultures; CRP values were also significantly higher in the bacteraemic patients. Both PCT and CRP had a good ability to discriminate bacteraemia from non-infectious SIRS, with the area under receiver operating characteristics (ROC) curves for PCT being 0.8 and for CRP being 0.82. However neither PCT or CRP was able to discriminate patients with localized sepsis from those without. Utilizing both tests resulted in a more sensitive screen than either one alone, while PCT was a more accurate diagnostic test for bacteraemia than CRP. The PCT value also differed between those who died in hospital and those who survived. Measurement of PCT alone or in combination with CRP can aid discrimination of septicaemia/bacteriemia with associated SIRS from non-infectious SIRS in an Australian ICU setting.

Australia↗

PubMed2002

Association between the APOE genotype and psychopathologic symptoms in Alzheimer's disease.

BACKGROUND: Psychiatric symptoms occur frequently in the course of AD, are a frequent contributor to institutionalization, predict cognitive decline and death, and often require treatment with psychotropic medications. Previous studies investigating the association between APOE genotype and psychiatric symptomatology in AD have reported contradictory results. OBJECTIVE: To determine whether APOE genotype predicts incident psychiatric symptomatology in patients with AD. METHODS: Eighty-seven patients with AD at early stages and no psychiatric history were followed semiannually for up to 9.3 years (mean 5.5 years) for development of delusions, illusions, hallucinations, behavioral symptoms, and depression. Cox proportional hazards models were used to examine the relative risk for incident psychiatric symptomatology (outcome) in relation to APOE genotype (predictor). RESULTS: The presence of one epsilon4 allele carried a 2.5-fold risk, whereas the presence of two epsilon4 alleles carried a 5.6-fold risk for development of delusions. The associations remained significant even when age, ethnicity, sex, education, duration of disease, and cognitive and functional performance were controlled for. The presence of two epsilon4 alleles was associated with reduced risk for developing hallucinations in the adjusted analysis only. No significant associations were detected between APOE genotype and the incidence of illusions, behavioral symptoms, or depression. CONCLUSION: The presence of one or more epsilon4 alleles is a significant predictor for the incidence of delusions in the course of AD.

Aged↗

PubMed2001

Beta-amyloid activates the mitogen-activated protein kinase cascade via hippocampal alpha7 nicotinic acetylcholine receptors: In vitro and in vivo mechanisms related to Alzheimer's disease.

Alzheimer's Disease (AD) is the most common of the senile dementias, the prevalence of which is increasing rapidly, with a projected 14 million affected worldwide by 2025. The signal transduction mechanisms that underlie the learning and memory derangements in AD are poorly understood. beta-Amyloid (Abeta) peptides are elevated in brain tissue of AD patients and are the principal component of amyloid plaques, a major criterion for postmortem diagnosis of the disease. Using acute and organotypic hippocampal slice preparations, we demonstrate that Abeta peptide 1-42 (Abeta42) couples to the mitogen-activated protein kinase (MAPK) cascade via alpha7 nicotinic acetylcholine receptors (nAChRs). In vivo elevation of Abeta, such as that exhibited in an animal model for AD, leads to the upregulation of alpha7 nAChR protein. alpha7 nAChR upregulation occurs concomitantly with the downregulation of the 42 kDa isoform of extracellular signal-regulated kinase (ERK2) MAPK in hippocampi of aged animals. The phosphorylation state of a transcriptional mediator of long-term potentiation and a downstream target of the ERK MAPK cascade, the cAMP-regulatory element binding (CREB) protein, were affected also. These findings support the model that derangement of hippocampus signal transduction cascades in AD arises as a consequence of increased Abeta burden and chronic activation of the ERK MAPK cascade in an alpha7 nAChR-dependent manner that eventually leads to the downregulation of ERK2 MAPK and decreased phosphorylation of CREB protein.

Aging↗

PubMed2001

Absence of mitochondrial superoxide dismutase results in a murine hemolytic anemia responsive to therapy with a catalytic antioxidant.

Manganese superoxide dismutase 2 (SOD2) is a critical component of the mitochondrial pathway for detoxification of O2(-), and targeted disruption of this locus leads to embryonic or neonatal lethality in mice. To follow the effects of SOD2 deficiency in cells over a longer time course, we created hematopoietic chimeras in which all blood cells are derived from fetal liver stem cells of Sod2 knockout, heterozygous, or wild-type littermates. Stem cells of each genotype efficiently rescued hematopoiesis and allowed long-term survival of lethally irradiated host animals. Peripheral blood analysis of leukocyte populations revealed no differences in reconstitution kinetics of T cells, B cells, or myeloid cells when comparing Sod2(+/+), Sod2(-/-), and Sod2(+/-) fetal liver recipients. However, animals receiving Sod2(-/-) cells were persistently anemic, with findings suggestive of a hemolytic process. Loss of SOD2 in erythroid progenitor cells results in enhanced protein oxidative damage, altered membrane deformation, and reduced survival of red cells. Treatment of anemic animals with Euk-8, a catalytic antioxidant with both SOD and catalase activities, significantly corrected this oxidative stress-induced condition. Such therapy may prove useful in treatment of human disorders such as sideroblastic anemia, which SOD2 deficiency most closely resembles.

Anemia, Hemolytic↗

PubMed2001

Incidence of AD in African-Americans, Caribbean Hispanics, and Caucasians in northern Manhattan.

OBJECTIVE: To compare the incidence rates for AD among elderly African-American, Caribbean Hispanic, and white individuals and to determine whether coincident cerebrovascular disease contributes to the inconsistency in reported differences among ethnic groups. METHODS: This was a population-based, longitudinal study over a 7-year period in the Washington Heights and Inwood communities of New York City. Annual incidence rates for AD were calculated and compared by ethnic group, and cumulative incidence adjusted for differences in education, diabetes, cardiovascular risk factors, and stroke was calculated. RESULTS: The age-specific incidence rate for probable and possible AD was 1.3% (95% CI, 0.8 to 1.7) per person-year between the ages of 65 and 74 years, 4.0% (95% CI, 3.2 to 4.8) per person-year between ages 75 and 84 years, and 7.9% (95% CI, 5.5 to 10.5) per person-year for ages 85 and older. Compared to white individuals, the cumulative incidence of AD to age 90 years was increased twofold among African-American and Caribbean Hispanic individuals. Adjustment for differences in number of years of education, illiteracy, or a history of stroke, hypertension, heart disease, or diabetes did not change the disproportionate risks among the three ethnic groups. CONCLUSION: The incidence rate for AD was significantly higher among African-American and Caribbean Hispanic elderly individuals compared white individuals. The presence of clinically apparent cardiovascular or cerebrovascular disease did not contribute to the increased risk of disease. Because the proportion of African-American and Caribbean Hispanic individuals reaching ages 65 and older in the United States is increasing more rapidly than the proportion of white individuals, it is imperative that this disparity in health among the elderly be understood.

Aged↗

PubMed2001

Characterization of baboon (Papio hamadryas) milk proteins.

The major proteins of baboon milk were identified as beta-lactoglobulin (beta LG), alpha-lactalbumin (alpha LA), lysozyme, lactoferrin, casein, and albumin by immobiline isoelectric focusing, SDS-PAGE, immunoblotting of gels with rabbit antisera to human alpha LA, lysozyme, and albumin and bovine beta LG and casein, and N-terminal sequencing of proteins blotted from gels. The first 30 N-terminal residues of baboon beta LG are identical to those of macaque (Macaca fasicularis) beta LG except for a (D/N) polymorphism at residue 2. The complete cDNA sequence and derived amino acid composition of beta LG were elucidated using RT-PCR amplification of poly(A)+ mRNA purified from lactating mammary gland. Baboon beta LG consists of 168 amino acid residues (M(r) 20,750) and is the longest beta LG identified to date. beta LG and alpha LA polymorphisms with three (A, B, and C) and two (A and B) variants, respectively, were detected by immobiline IEF, pH 4-6, of individual baboon milk samples at varying stages of lactation.

Albumins↗

PubMed2001

Prognostic importance of the axillary lymph node ratio in autologous transplantation for high-risk stage II/III breast cancer.

The role of autologous peripheral blood progenitor cell (PBPC) transplantation for high-risk stage II/III breast cancer remains controversial. New prognostic indicators defining subsets of patients who may benefit from autologous PBPC transplantation would be clinically useful. The axillary lymph node ratio, defined by the total number of axillary nodes involved with cancer divided by the number of axillary nodes surgically sampled, has been reported to be of potential prognostic importance in transplantation for high-risk, stage II/III breast cancer. We therefore retrospectively reviewed 111 women with high-risk, stage II/III breast cancer with at least four positive axillary lymph nodes undergoing autologous PBPC transplantation from 1991 to June 1999. None of the patients had received prior radiotherapy and all had completed one, and only one, course of at least three cycles of adjuvant chemotherapy. The median number of axillary nodes sampled was 20 (range 6-40) and the median number of positive axillary nodes was 12 (range 4-35). The median node ratio, dividing the number of positive nodes by the number of sampled nodes, was 0.68. Event-free survival was strongly influenced by node ratio. Patients having a node ratio of < 0.7 had a 5-year event-free survival of 68%, vs those with a node ratio of > or = 0.7 with a 5-year event-free survival of 46% (P = 0.03). Forty percent of patients with a high node ratio have relapsed vs 20% with a low node ratio (P = 0.02). Multivariate analysis revealed that positive estrogen receptor status and a node ratio of < 0.7 were independent factors related to better event-free survival (P = 0.0001 and P = 0.004, respectively). We conclude that patients having a node ratio of < 0.7 have a significantly better prognosis following autologous PBPC transplantation than do patients with a ratio > or = 0.7.

Adult↗

PubMed2001

Persistent mobility deficit in the absence of deficits in activities of daily living: a risk factor for mortality.

OBJECTIVES: To investigate the extent to which self-reported mobility deficit in the absence of impairment in activities of daily living (ADL) is associated with elevated mortality risk. DESIGN: Prospective cohort study, with annual assessments of mobility and ADL status and ongoing monitoring of vital status. SETTING: Population-based cohort drawn from Medicare enrollees in New York City. PARTICIPANTS: One thousand two hundred ninety-eight older adults reporting functional status at baseline (1992-1994) and 2 years later. MEASUREMENTS: Subjects reported mobility (e.g., walking, climbing stairs, and rising from a chair) and ADL (e.g., bathing, toilet use, dressing, grooming, and feeding) limitations. Two-year functional status trajectories were noted. We used two additional follow-up periods, at 2 and 4 years, to examine the likelihood that older people with mobility deficit may face an increased risk of death without first passing through a state of enduring ADL disability. RESULTS: At 2 years, 12.7% had incident mobility deficit without ADL disability, and 21.3% were persistently disabled in mobility without ADL disability. Relative to subjects free of disability at baseline and follow-up, risk of mortality in the incident mobility deficit group was elevated at 2 and 4 years but did not achieve statistical significance. By contrast, for subjects with persistent mobility impairment who did not report ADL impairment, the mortality risk was significantly elevated both at 2 years (relative risk (RR) = 2.5; 95% confidence interval (CI) = 1.1-5.7)) and 4 years (RR = 2.9; 95% CI = 1.7-4.9)) of follow-up. Mortality was significantly elevated in this group in analyses restricted to respondents with no or only one comorbid condition. CONCLUSION: Continuing, self-reported mobility impairment in the absence of ADL deficit is a risk factor for mortality. Older people with self-reported mobility deficit face an increased risk of mortality without first passing through enduring states of ADL disability.

Activities of Daily Living↗